DescriptionAn in-depth report on the causes, diagnosis, treatment, and prevention of fibromyalgia.
Conditions with Similar Symptoms
Between 10% and 30% of all doctors' office visits are due to symptoms that resemble those of fibromyalgia, including fatigue, malaise, and widespread muscle pain. No laboratory test can confirm a diagnosis of fibromyalgia, and if tests for tender spots are ambiguous, physicians will rule out other conditions. It should be noted that a diagnosis of many of these disorders may not always rule out fibromyalgia, since it can accompany other common and similar conditions.
Conditions That Do Not Rule Out Fibromyalgia
Chronic fatigue syndrome, myofascial pain syndrome, depression, primary headaches, and, certain stress-related disorders commonly occur with fibromyalgia and have overlapping symptoms. In fact, some experts believe these disorders so often interact that they may all be part of one general condition.
Other conditions may also occur that are similar to fibromyalgia but do not rule out a diagnosis of fibromyalgia. They include:
Some tests may be positive for one or more of these diseases. However, if the results are ambiguous or weak or if they have been treated successfully, fibromyalgia should not be ruled out if the patient still also meets the criteria for it.
Conditions That Usually Rule Out Fibromyalgia
Rheumatoid Arthritis and Other Autoimmune Diseases. Many autoimmune diseases, in which the person's immune system attacks the body's own tissues, resemble fibromyalgia. (Fibromyalgia, itself, may be an autoimmune disorder.) These diseases, like fibromyalgia, also occur more often in women than in men, and early symptoms are often muscle and joint pain and fatigue. The following are some autoimmune disorders that may be confused with fibromyalgia:
Autoimmune diseases generally evolve slowly. Even if a physician determines that a patient is most likely to have fibromyalgia, he or she should keep track of any changes in symptoms over time in case one of these illnesses is actually present.
Lyme Disease. Early Lyme disease can usually be correctly diagnosed, but a delayed response or recurrence of this disorder may be mistaken for fibromyalgia. Some experts believe that between 15% and 50% of patients referred to clinics for Lyme disease actually have fibromyalgia. Late Lyme disease can usually (but not always) be ruled out using laboratory tests that identify the infectious organism (spirochete) that causes this tick-borne disease. If fibromyalgia patients are incorrectly diagnosed and treated for Lyme disease with prolonged courses of antibiotics, the drugs may have serious side effects.
Drugs and Alcohol. Fatigue is a side effect of many prescription and over-the-counter medications, such as antihistamines. In addition, dependency on or abuse of alcohol or illicit drugs may manifest as persistent fatigue. Medications should be considered as a possible cause of fatigue if an individual has recently started, stopped, or changed medications. Withdrawal from caffeine can produce depression, fatigue, and headache.
Polymyalgia Rheumatica. Polymyalgia rheumatica is a condition that causes pain and stiffness and generally occurs in older women. Tender points are also present with this disorder, although they almost always occur in the hip and shoulder area. Morning stiffness is common, and patients may also experience fever, weight loss, and fatigue. Elevated erythrocyte sedimentation rates (ESR or sed rates), detected from results of a blood test, can suggest polymyalgia rheumatica. (Elevated sed rates, however, also occur with other conditions as well.) The condition often resolves in about a year, but there is a risk of persistent disease. Worse, it is associated with a rare condition called temporal arteritis, which causes blindness if not healed, so an accurate diagnosis of polymyalgia rheumatica is important.
Other Diseases That May Rule Out Fibromyalgia. Many diseases and conditions, both benign and serious, can fully explain prolonged or chronic fatigue, including the following: